7k3's have a factory nominal chamber size of 96 cc's. If everything else about the engine is factory nominal +0.030 (that's a big if because there's lots of room for variance in there), then that engine is right at 8.144:1 which is a little on the low side. However, running the 670's would put you up around 10.4:1 which (in my opinion) would be too high for pump gas. Plus, the 670's are closed chamber heads and as such, need quite a bit of ignition advance to work well - just what you DON'T want if you're already over the limit on compression.
If your engine has been zero decked it could be up around 8.5:1 (still low).
Don't worry about "pushing" compression ratio. The truth is, changing compression alone doesn't make much difference in power output. On a street engine, it's almost never "worth" trying to push one right to the edge. The small amount of power (and I'm talking 10 hp or less) is rarely worth all the associated headaches and risk of grenading the motor.
It's very important to actually measure your chambers, and everything else about that engine, before you start in on it. The heads may have already been milled some, the block may have already been zero decked ---- all of which will have an effect on actual compression ratio.
For example if those heads have been milled about .040-.045 or so and have chambers that are now 86 cc's, and the block zero decked, then it'll be at 9.150:1 which is a pretty good place to be with iron heads.
That Crower 60244 is a fairly rowdy cam for a 400 street engine. You may find it's borderline for running vacuum accessories like power brakes.
HOWEVER - let's say you were to swap out the rotating assembly, crank, rods, and pistons --- transform it into a 461 (4.25 stoke, +035 overbore) --- then with those heads and flattops you'd be at 9.1:1 (nominal deck) or 9.4:1 (zero deck), and I promise you'd have a huge smile on your face every time you stood on it
Plus, the extra inches would make that cam a lot more streetable.